The body of a missing 4-year-old boy who became the subject of an Amber Alert across Riverside, Orange and San Diego counties Sunday morning has been found by divers in Mission Bay.

Wesley Hilaire was last seen walking near the water in the 2800 block of E. Mission Bay Drive at about 7:45 p.m. Saturday.

Witnesses told San Diego police they saw the boy walk away with a man during a family outing at Mission Bay Park in San Diego.

Hilaire was visiting the beach for the first time with his aunt and other family members. The family was packing up for the day when they noticed him missing, San Diego police told KGTV, the ABC affiliate in San Diego.

San Diego police issued an Amber Alert for Wesley at 2 a.m. amid worries he'd been abducted while at the beach.

The boy's remains were found 100 yards offshore by a Harbor Patrol sonar boat at 11 a.m. Sunday. Police say it appears he accidentally drowned.